1. Field of the Invention
The present invention relates to a battery coupler and, in particular, to a battery coupler which is used in a video tape recorder (VTR) integral with a camera.
2. Description of the Related Art
1 With the spread of a VTR integral with a camera, the use of a battery coupler has been popularized so that, even when taking pictures indoors or in the evening, lack of light can be eliminated to thereby provide a satisfactory picture quality.
Also, there have been increasing photographers who use a microphone having a high performance in order to improve the quality of sound in addition to the picture quality. In use, the battery coupler and the high-performance microphone are mounted onto a shoe for accessory mounting arranged on a camera main body.
2 In general, the VTR integral with a camera, an electronic still camera and the like consume a relatively larger amount of electric power. This requires a battery which is capable of supplying a relatively larger amount of electric power. And, in view of running costs, and exclusive, chargeable battery (which is referred hereinafter to as a battery simply) is used in most of cases. This battery can be charged and used successively after it is used (discharged) for a predetermined period of time.
To charge the battery, at first, a plug of battery charger is electrically connected to an AC socket outlet, and then the battery is removed from the camera main body and set to the battery charger. After the battery is set to the battery charger, normally in the lapse of 1 to 2 hours the charging of the battery is completed. Then the battery is disconnected from the battery charger and is mounted to the camera main body again. Thereafter, the plug of the battery charger is removed from the AC socket outlet and the battery charger is then stored. This completes a series of battery charging operations.
3 Further, in the battery coupler discussed above in 1 disclosed in Publication of Laid-open Utility Model Application (Jikkai) No.61-100078, for example, a video light mounting plate is mounted to a mounting shoe provided on the camera main body and a contact on the video light side disposed in the mounting plate is connected to another contact on the camera main body disposed in the mounting shoe, so that the video light can be turned on by means of a battery provided on the camera main body.
Referring now to FIG. 17, there is shown another conventional battery coupler with battery which comprises 2 halogen lamps 12 disposed in the front portion of a casing 10 and a video light battery 14 disposed in the rear portion of the casing 10. The video light battery 14 and the halogen lamps 12 can be electrically connected or can be brought into electrically engageable connection with each other by operating a mode change-over switch 16 which is provided in the casing 10. Here, numeral 18 designates a switch which is used to change over one mode into another mode or vice versa; in one mode one of the halogen lamps 10 is turned on, and in another mode both of the halogen lamps 10 are turned on. 20 stands for a lock lever for the video light battery 14.
In the bottom portion of the battery coupler constructed in this manner, there is disposed a mounting plate 22, through which plate 22 the battery coupler can be mounted onto a mounting shoe (not, shown) disposed in the main body of a VTR integral with a camera.
Also, the battery coupler shown in FIG. 17 further comprises a connecting cord 24. The connecting cord 24 can be connected to a terminal (not shown) of the VTR integral with a camera to thereby receive an electric signal from the VTR integral with a camera, and the thus received electric signal can be used to turn on the halogen lamp(s) 12. For this reason, for example, when the VTR integral with a camera is in its (stand-by) state or in its (REC) state, the halogen lamp 12 is automatically turned on.
However, the above-mentioned prior art battery couplers respectively have problems as follows: